/*
 * node.c: udp packet processing
 *
 * Copyright (c) 2013-2019 Cisco and/or its affiliates.
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at:
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include <vlib/vlib.h>
#include <vnet/pg/pg.h>
#include <vnet/udp/udp.h>
#include <vnet/udp/udp_packet.h>
#include <vppinfra/sparse_vec.h>

#define foreach_udp_local_next                  \
  _ (PUNT4, "ip4-punt")                         \
  _ (PUNT6, "ip6-punt")                         \
  _ (DROP4, "ip4-drop")                         \
  _ (DROP6, "ip6-drop")                         \
  _ (ICMP4_ERROR, "ip4-icmp-error")             \
  _ (ICMP6_ERROR, "ip6-icmp-error")

typedef enum
{
#define _(s,n) UDP_LOCAL_NEXT_##s,
  foreach_udp_local_next
#undef _
    UDP_LOCAL_N_NEXT,
} udp_local_next_t;

#define udp_local_next_drop(is_ip4)      ((is_ip4) ? UDP_LOCAL_NEXT_DROP4 : UDP_LOCAL_NEXT_DROP6)
#define udp_local_next_punt(is_ip4)      ((is_ip4) ? UDP_LOCAL_NEXT_PUNT4 : UDP_LOCAL_NEXT_PUNT6)

typedef struct
{
  u16 src_port;
  u16 dst_port;
  u8 bound;
} udp_local_rx_trace_t;

#ifndef CLIB_MARCH_VARIANT
u8 *
format_udp_rx_trace (u8 * s, va_list * args)
{
  CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
  CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
  udp_local_rx_trace_t *t = va_arg (*args, udp_local_rx_trace_t *);

  s = format (s, "UDP: src-port %d dst-port %d%s",
	      clib_net_to_host_u16 (t->src_port),
	      clib_net_to_host_u16 (t->dst_port),
	      t->bound ? "" : " (no listener)");
  return s;
}
#endif /* CLIB_MARCH_VARIANT */

always_inline uword
udp46_local_inline (vlib_main_t * vm,
		    vlib_node_runtime_t * node,
		    vlib_frame_t * from_frame, int is_ip4)
{
  udp_main_t *um = &udp_main;
  __attribute__ ((unused)) u32 n_left_from, next_index, *from, *to_next;
  word n_no_listener = 0;
  u8 punt_unknown = is_ip4 ? um->punt_unknown4 : um->punt_unknown6;

  from = vlib_frame_vector_args (from_frame);
  n_left_from = from_frame->n_vectors;

  next_index = node->cached_next_index;

  while (n_left_from > 0)
    {
      u32 n_left_to_next;

      vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);

      while (n_left_from >= 4 && n_left_to_next >= 2)
	{
	  u32 bi0, bi1;
	  vlib_buffer_t *b0, *b1;
	  udp_header_t *h0 = 0, *h1 = 0;
	  u32 i0, i1, dst_port0, dst_port1;
	  u32 advance0, advance1;
	  u32 error0, next0, error1, next1;

	  /* Prefetch next iteration. */
	  {
	    vlib_buffer_t *p2, *p3;

	    p2 = vlib_get_buffer (vm, from[2]);
	    p3 = vlib_get_buffer (vm, from[3]);

	    vlib_prefetch_buffer_header (p2, LOAD);
	    vlib_prefetch_buffer_header (p3, LOAD);

	    CLIB_PREFETCH (p2->data, sizeof (h0[0]), LOAD);
	    CLIB_PREFETCH (p3->data, sizeof (h1[0]), LOAD);
	  }

	  bi0 = from[0];
	  bi1 = from[1];
	  to_next[0] = bi0;
	  to_next[1] = bi1;
	  from += 2;
	  to_next += 2;
	  n_left_to_next -= 2;
	  n_left_from -= 2;

	  b0 = vlib_get_buffer (vm, bi0);
	  b1 = vlib_get_buffer (vm, bi1);

	  /* ip4/6_local hands us the ip header, not the udp header */
	  if (is_ip4)
	    {
	      advance0 = sizeof (ip4_header_t);
	      advance1 = sizeof (ip4_header_t);
	    }
	  else
	    {
	      advance0 = sizeof (ip6_header_t);
	      advance1 = sizeof (ip6_header_t);
	    }

	  if (PREDICT_FALSE (b0->current_length < advance0 + sizeof (*h0)))
	    {
	      error0 = UDP_ERROR_LENGTH_ERROR;
	      next0 = udp_local_next_drop (is_ip4);
	    }
	  else
	    {
	      vlib_buffer_advance (b0, advance0);
	      h0 = vlib_buffer_get_current (b0);
	      error0 = next0 = 0;
	      if (PREDICT_FALSE (clib_net_to_host_u16 (h0->length) >
				 vlib_buffer_length_in_chain (vm, b0)))
		{
		  error0 = UDP_ERROR_LENGTH_ERROR;
		  next0 = udp_local_next_drop (is_ip4);
		}
	    }

	  if (PREDICT_FALSE (b1->current_length < advance1 + sizeof (*h1)))
	    {
	      error1 = UDP_ERROR_LENGTH_ERROR;
	      next1 = udp_local_next_drop (is_ip4);
	    }
	  else
	    {
	      vlib_buffer_advance (b1, advance1);
	      h1 = vlib_buffer_get_current (b1);
	      error1 = next1 = 0;
	      if (PREDICT_FALSE (clib_net_to_host_u16 (h1->length) >
				 vlib_buffer_length_in_chain (vm, b1)))
		{
		  error1 = UDP_ERROR_LENGTH_ERROR;
		  next1 = udp_local_next_drop (is_ip4);
		}
	    }

	  /* Index sparse array with network byte order. */
	  dst_port0 = (error0 == 0) ? h0->dst_port : 0;
	  dst_port1 = (error1 == 0) ? h1->dst_port : 0;
	  sparse_vec_index2 (is_ip4 ? um->next_by_dst_port4 :
			     um->next_by_dst_port6,
			     dst_port0, dst_port1, &i0, &i1);
	  next0 = (error0 == 0) ?
	    vec_elt (is_ip4 ? um->next_by_dst_port4 : um->next_by_dst_port6,
		     i0) : next0;
	  next1 = (error1 == 0) ?
	    vec_elt (is_ip4 ? um->next_by_dst_port4 : um->next_by_dst_port6,
		     i1) : next1;

	  if (PREDICT_FALSE (i0 == SPARSE_VEC_INVALID_INDEX))
	    {
	      // move the pointer back so icmp-error can find the
	      // ip packet header
	      vlib_buffer_advance (b0, -(word) advance0);

	      if (PREDICT_FALSE (punt_unknown))
		{
		  b0->error = node->errors[UDP_ERROR_PUNT];
		  next0 = udp_local_next_punt (is_ip4);
		}
	      else if (is_ip4)
		{
		  icmp4_error_set_vnet_buffer (b0,
					       ICMP4_destination_unreachable,
					       ICMP4_destination_unreachable_port_unreachable,
					       0);
		  next0 = UDP_LOCAL_NEXT_ICMP4_ERROR;
		  n_no_listener++;
		}
	      else
		{
		  icmp6_error_set_vnet_buffer (b0,
					       ICMP6_destination_unreachable,
					       ICMP6_destination_unreachable_port_unreachable,
					       0);
		  next0 = UDP_LOCAL_NEXT_ICMP6_ERROR;
		  n_no_listener++;
		}
	    }
	  else
	    {
	      b0->error = node->errors[UDP_ERROR_NONE];
	      // advance to the payload
	      vlib_buffer_advance (b0, sizeof (*h0));
	    }

	  if (PREDICT_FALSE (i1 == SPARSE_VEC_INVALID_INDEX))
	    {
	      // move the pointer back so icmp-error can find the
	      // ip packet header
	      vlib_buffer_advance (b1, -(word) advance1);

	      if (PREDICT_FALSE (punt_unknown))
		{
		  b1->error = node->errors[UDP_ERROR_PUNT];
		  next1 = udp_local_next_punt (is_ip4);
		}
	      else if (is_ip4)
		{
		  icmp4_error_set_vnet_buffer (b1,
					       ICMP4_destination_unreachable,
					       ICMP4_destination_unreachable_port_unreachable,
					       0);
		  next1 = UDP_LOCAL_NEXT_ICMP4_ERROR;
		  n_no_listener++;
		}
	      else
		{
		  icmp6_error_set_vnet_buffer (b1,
					       ICMP6_destination_unreachable,
					       ICMP6_destination_unreachable_port_unreachable,
					       0);
		  next1 = UDP_LOCAL_NEXT_ICMP6_ERROR;
		  n_no_listener++;
		}
	    }
	  else
	    {
	      b1->error = node->errors[UDP_ERROR_NONE];
	      // advance to the payload
	      vlib_buffer_advance (b1, sizeof (*h1));
	    }

	  if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
	    {
	      udp_local_rx_trace_t *tr = vlib_add_trace (vm, node,
							 b0, sizeof (*tr));
	      if (b0->error != node->errors[UDP_ERROR_LENGTH_ERROR])
		{
		  tr->src_port = h0 ? h0->src_port : 0;
		  tr->dst_port = h0 ? h0->dst_port : 0;
		  tr->bound = (next0 != UDP_LOCAL_NEXT_ICMP4_ERROR &&
			       next0 != UDP_LOCAL_NEXT_ICMP6_ERROR);
		}
	    }
	  if (PREDICT_FALSE (b1->flags & VLIB_BUFFER_IS_TRACED))
	    {
	      udp_local_rx_trace_t *tr = vlib_add_trace (vm, node,
							 b1, sizeof (*tr));
	      if (b1->error != node->errors[UDP_ERROR_LENGTH_ERROR])
		{
		  tr->src_port = h1 ? h1->src_port : 0;
		  tr->dst_port = h1 ? h1->dst_port : 0;
		  tr->bound = (next1 != UDP_LOCAL_NEXT_ICMP4_ERROR &&
			       next1 != UDP_LOCAL_NEXT_ICMP6_ERROR);
		}
	    }

	  vlib_validate_buffer_enqueue_x2 (vm, node, next_index,
					   to_next, n_left_to_next,
					   bi0, bi1, next0, next1);
	}

      while (n_left_from > 0 && n_left_to_next > 0)
	{
	  u32 bi0;
	  vlib_buffer_t *b0;
	  udp_header_t *h0 = 0;
	  u32 i0, next0;
	  u32 advance0;

	  bi0 = from[0];
	  to_next[0] = bi0;
	  from += 1;
	  to_next += 1;
	  n_left_from -= 1;
	  n_left_to_next -= 1;

	  b0 = vlib_get_buffer (vm, bi0);

	  /* ip4/6_local hands us the ip header, not the udp header */
	  if (is_ip4)
	    advance0 = sizeof (ip4_header_t);
	  else
	    advance0 = sizeof (ip6_header_t);

	  if (PREDICT_FALSE (b0->current_length < advance0 + sizeof (*h0)))
	    {
	      b0->error = node->errors[UDP_ERROR_LENGTH_ERROR];
	      next0 = udp_local_next_drop (is_ip4);
	      goto trace_x1;
	    }

	  vlib_buffer_advance (b0, advance0);

	  h0 = vlib_buffer_get_current (b0);

	  if (PREDICT_TRUE (clib_net_to_host_u16 (h0->length) <=
			    vlib_buffer_length_in_chain (vm, b0)))
	    {
	      i0 = sparse_vec_index (is_ip4 ? um->next_by_dst_port4 :
				     um->next_by_dst_port6, h0->dst_port);
	      next0 = vec_elt (is_ip4 ? um->next_by_dst_port4 :
			       um->next_by_dst_port6, i0);

	      if (PREDICT_FALSE (i0 == SPARSE_VEC_INVALID_INDEX))
		{
		  // move the pointer back so icmp-error can find the
		  // ip packet header
		  vlib_buffer_advance (b0, -(word) advance0);

		  if (PREDICT_FALSE (punt_unknown))
		    {
		      b0->error = node->errors[UDP_ERROR_PUNT];
		      next0 = udp_local_next_punt (is_ip4);
		    }
		  else if (is_ip4)
		    {
		      icmp4_error_set_vnet_buffer (b0,
						   ICMP4_destination_unreachable,
						   ICMP4_destination_unreachable_port_unreachable,
						   0);
		      next0 = UDP_LOCAL_NEXT_ICMP4_ERROR;
		      n_no_listener++;
		    }
		  else
		    {
		      icmp6_error_set_vnet_buffer (b0,
						   ICMP6_destination_unreachable,
						   ICMP6_destination_unreachable_port_unreachable,
						   0);
		      next0 = UDP_LOCAL_NEXT_ICMP6_ERROR;
		      n_no_listener++;
		    }
		}
	      else
		{
		  b0->error = node->errors[UDP_ERROR_NONE];
		  // advance to the payload
		  vlib_buffer_advance (b0, sizeof (*h0));
		}
	    }
	  else
	    {
	      b0->error = node->errors[UDP_ERROR_LENGTH_ERROR];
	      next0 = udp_local_next_drop (is_ip4);
	    }

	trace_x1:
	  if (PREDICT_FALSE (b0->flags & VLIB_BUFFER_IS_TRACED))
	    {
	      udp_local_rx_trace_t *tr = vlib_add_trace (vm, node,
							 b0, sizeof (*tr));
	      if (b0->error != node->errors[UDP_ERROR_LENGTH_ERROR])
		{
		  tr->src_port = h0->src_port;
		  tr->dst_port = h0->dst_port;
		  tr->bound = (next0 != UDP_LOCAL_NEXT_ICMP4_ERROR &&
			       next0 != UDP_LOCAL_NEXT_ICMP6_ERROR);
		}
	    }

	  vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
					   to_next, n_left_to_next,
					   bi0, next0);
	}

      vlib_put_next_frame (vm, node, next_index, n_left_to_next);
    }
  vlib_error_count (vm, node->node_index, UDP_ERROR_NO_LISTENER,
		    n_no_listener);
  return from_frame->n_vectors;
}

static char *udp_error_strings[] = {
#define udp_error(n,s) s,
#include "udp_error.def"
#undef udp_error
};

VLIB_NODE_FN (udp4_local_node) (vlib_main_t * vm,
				vlib_node_runtime_t * node,
				vlib_frame_t * from_frame)
{
  return udp46_local_inline (vm, node, from_frame, 1 /* is_ip4 */ );
}

VLIB_NODE_FN (udp6_local_node) (vlib_main_t * vm,
				vlib_node_runtime_t * node,
				vlib_frame_t * from_frame)
{
  return udp46_local_inline (vm, node, from_frame, 0 /* is_ip4 */ );
}

/* *INDENT-OFF* */
VLIB_REGISTER_NODE (udp4_local_node) = {
  .name = "ip4-udp-lookup",
  /* Takes a vector of packets. */
  .vector_size = sizeof (u32),

  .n_errors = UDP_N_ERROR,
  .error_strings = udp_error_strings,

  .n_next_nodes = UDP_LOCAL_N_NEXT,
  .next_nodes = {
#define _(s,n) [UDP_LOCAL_NEXT_##s] = n,
    foreach_udp_local_next
#undef _
  },

  .format_buffer = format_udp_header,
  .format_trace = format_udp_rx_trace,
  .unformat_buffer = unformat_udp_header,
};
/* *INDENT-ON* */

/* *INDENT-OFF* */
VLIB_REGISTER_NODE (udp6_local_node) = {
  .name = "ip6-udp-lookup",
  /* Takes a vector of packets. */
  .vector_size = sizeof (u32),

  .n_errors = UDP_N_ERROR,
  .error_strings = udp_error_strings,

  .n_next_nodes = UDP_LOCAL_N_NEXT,
  .next_nodes = {
#define _(s,n) [UDP_LOCAL_NEXT_##s] = n,
    foreach_udp_local_next
#undef _
  },

  .format_buffer = format_udp_header,
  .format_trace = format_udp_rx_trace,
  .unformat_buffer = unformat_udp_header,
};
/* *INDENT-ON* */

#ifndef CLIB_MARCH_VARIANT
static void
add_dst_port (udp_main_t * um,
	      udp_dst_port_t dst_port, char *dst_port_name, u8 is_ip4)
{
  udp_dst_port_info_t *pi;
  u32 i;

  vec_add2 (um->dst_port_infos[is_ip4], pi, 1);
  i = pi - um->dst_port_infos[is_ip4];

  pi->name = dst_port_name;
  pi->dst_port = dst_port;
  pi->next_index = pi->node_index = ~0;

  hash_set (um->dst_port_info_by_dst_port[is_ip4], dst_port, i);

  if (pi->name)
    hash_set_mem (um->dst_port_info_by_name[is_ip4], pi->name, i);
}

void
udp_register_dst_port (vlib_main_t * vm,
		       udp_dst_port_t dst_port, u32 node_index, u8 is_ip4)
{
  udp_main_t *um = &udp_main;
  udp_dst_port_info_t *pi;
  u16 *n;

  {
    clib_error_t *error = vlib_call_init_function (vm, udp_local_init);
    if (error)
      clib_error_report (error);
  }

  pi = udp_get_dst_port_info (um, dst_port, is_ip4);
  if (!pi)
    {
      add_dst_port (um, dst_port, 0, is_ip4);
      pi = udp_get_dst_port_info (um, dst_port, is_ip4);
      ASSERT (pi);
    }

  pi->node_index = node_index;
  pi->next_index = vlib_node_add_next (vm,
				       is_ip4 ? udp4_local_node.index
				       : udp6_local_node.index, node_index);

  /* Setup udp protocol -> next index sparse vector mapping. */
  if (is_ip4)
    n = sparse_vec_validate (um->next_by_dst_port4,
			     clib_host_to_net_u16 (dst_port));
  else
    n = sparse_vec_validate (um->next_by_dst_port6,
			     clib_host_to_net_u16 (dst_port));

  n[0] = pi->next_index;
}

void
udp_unregister_dst_port (vlib_main_t * vm, udp_dst_port_t dst_port, u8 is_ip4)
{
  udp_main_t *um = &udp_main;
  udp_dst_port_info_t *pi;
  u16 *n;

  pi = udp_get_dst_port_info (um, dst_port, is_ip4);
  /* Not registered? Fagedaboudit */
  if (!pi)
    return;

  /* Kill the mapping. Don't bother killing the pi, it may be back. */
  if (is_ip4)
    n = sparse_vec_validate (um->next_by_dst_port4,
			     clib_host_to_net_u16 (dst_port));
  else
    n = sparse_vec_validate (um->next_by_dst_port6,
			     clib_host_to_net_u16 (dst_port));

  n[0] = SPARSE_VEC_INVALID_INDEX;
}

bool
udp_is_valid_dst_port (udp_dst_port_t dst_port, u8 is_ip4)
{
  udp_main_t *um = &udp_main;
  u16 *n;

  if (is_ip4)
    n = sparse_vec_validate (um->next_by_dst_port4,
			     clib_host_to_net_u16 (dst_port));
  else
    n = sparse_vec_validate (um->next_by_dst_port6,
			     clib_host_to_net_u16 (dst_port));

  return (n[0] != SPARSE_VEC_INVALID_INDEX);
}

void
udp_punt_unknown (vlib_main_t * vm, u8 is_ip4, u8 is_add)
{
  udp_main_t *um = &udp_main;
  {
    clib_error_t *error = vlib_call_init_function (vm, udp_local_init);
    if (error)
      clib_error_report (error);
  }

  if (is_ip4)
    um->punt_unknown4 = is_add;
  else
    um->punt_unknown6 = is_add;
}

/* Parse a UDP header. */
uword
unformat_udp_header (unformat_input_t * input, va_list * args)
{
  u8 **result = va_arg (*args, u8 **);
  udp_header_t *udp;
  __attribute__ ((unused)) int old_length;
  u16 src_port, dst_port;

  /* Allocate space for IP header. */
  {
    void *p;

    old_length = vec_len (*result);
    vec_add2 (*result, p, sizeof (ip4_header_t));
    udp = p;
  }

  clib_memset (udp, 0, sizeof (udp[0]));
  if (unformat (input, "src-port %d dst-port %d", &src_port, &dst_port))
    {
      udp->src_port = clib_host_to_net_u16 (src_port);
      udp->dst_port = clib_host_to_net_u16 (dst_port);
      return 1;
    }
  return 0;
}

static void
udp_setup_node (vlib_main_t * vm, u32 node_index)
{
  vlib_node_t *n = vlib_get_node (vm, node_index);
  pg_node_t *pn = pg_get_node (node_index);

  n->format_buffer = format_udp_header;
  n->unformat_buffer = unformat_udp_header;
  pn->unformat_edit = unformat_pg_udp_header;
}

clib_error_t *
udp_local_init (vlib_main_t * vm)
{
  udp_main_t *um = &udp_main;
  int i;

  {
    clib_error_t *error;
    error = vlib_call_init_function (vm, udp_init);
    if (error)
      clib_error_report (error);
  }


  for (i = 0; i < 2; i++)
    {
      um->dst_port_info_by_name[i] = hash_create_string (0, sizeof (uword));
      um->dst_port_info_by_dst_port[i] = hash_create (0, sizeof (uword));
    }

  udp_setup_node (vm, udp4_local_node.index);
  udp_setup_node (vm, udp6_local_node.index);

  um->punt_unknown4 = 0;
  um->punt_unknown6 = 0;

  um->next_by_dst_port4 = sparse_vec_new
    ( /* elt bytes */ sizeof (um->next_by_dst_port4[0]),
     /* bits in index */ BITS (((udp_header_t *) 0)->dst_port));

  um->next_by_dst_port6 = sparse_vec_new
    ( /* elt bytes */ sizeof (um->next_by_dst_port6[0]),
     /* bits in index */ BITS (((udp_header_t *) 0)->dst_port));

#define _(n,s) add_dst_port (um, UDP_DST_PORT_##s, #s, 1 /* is_ip4 */);
  foreach_udp4_dst_port
#undef _
#define _(n,s) add_dst_port (um, UDP_DST_PORT_##s, #s, 0 /* is_ip4 */);
    foreach_udp6_dst_port
#undef _
    ip4_register_protocol (IP_PROTOCOL_UDP, udp4_local_node.index);
  /* Note: ip6 differs from ip4, UDP is hotwired to ip6-udp-lookup */
  return 0;
}

VLIB_INIT_FUNCTION (udp_local_init);
#endif /* CLIB_MARCH_VARIANT */

/*
 * fd.io coding-style-patch-verification: ON
 *
 * Local Variables:
 * eval: (c-set-style "gnu")
 * End:
 */